1. Field of the Invention
The present invention relates to a device and a method for controlling a quantity control valve.
2. Description of Related Art
Published German patent application document DE 101 48 218 A1 describes a method for operating a fuel injection system using a quantity control valve. The known quantity control valve is implemented as a solenoid valve which has an armature and associated path limiting stops and which is electromagnetically activated by a magnetic coil. Quantity control valves of this type which are closed in the de-energized state of the magnetic coil are known from the market. In this case, for opening the quantity control valve the magnetic coil is controlled by a constant voltage or a clocked voltage (pulse width modulation (PWM)), causing the current in the magnetic coil to increase in a characteristic manner. After the voltage is switched off, the current drops back in a characteristic manner, causing the quantity control valve to close. Solenoid valves are also known which are open in the energized state of the coil. These solenoid valves are operated in a similar manner in which the solenoid valve opens when the voltage is switched off and the current undergoes a characteristic drop.
For the valve, which is closed in the de-energized state, disclosed in published German patent application document DE 101 48 218 A1, in order to prevent the armature from striking against the stop at full speed during the opening motion of the quantity control valve, which could result in significant noise generation, the electromagnetic actuating device is energized once again in a pulsed manner shortly before the opening motion ends. As a result of this current pulse, a decelerating force is exerted on the armature before it contacts the stop. The decelerating force causes the speed to be reduced, thus decreasing the noise from the stop.
Since the properties of the quantity control valve are different from one specimen to another, for the most effective reduction possible of the noise from the stop it is advantageous when the effect of the energization is not a function of the specimen properties.
German patent application document DE 10 2008 054 512, not pre-published, proposes that at least one parameter of the braking pulse is adapted to the specimen properties for controlling a quantity control valve which is activated by an electromagnetic actuating device.
However, this method imposes great demands on the control/regulation device on which the method is implemented. A less complicated method is desirable for reducing the demands on the control/regulation device.